The invention relates to an adjustment safeguard for a set screw that is rotatably supported in a housing, in particular for a set screw of a carburetor such as a diaphragm carburetor or the like of a hand-guided power tool such as a motor chainsaw or the like. The adjustment safeguard comprises a cap that is non-rotatably secured on the head of the set screw, wherein the cap is surrounded with minimal radial play by an approximately coaxially positioned sleeve, fast with the carburetor housing, and is received in the sleeve across its axial length. The cap has a projection that has correlated therewith a stop disposed in the rotational direction of the set screw inside the sleeve and fast with the carburetor housing.
U.S. Pat. No. 5,252,261 discloses an adjustment safeguard for the adjusting needle (set screw) of a carburetor that is comprised of a cap fixedly secured on the head of the set screw and surrounded with minimal radial play by a coaxially positioned sleeve fast with the carburetor housing. The cap has in rotational direction of the set screw a stop that is fast with the carburetor housing so that after positioning of the cap the user can adjust the set screw only by a limited rotational angle.
The cap is pushed onto a knurled section of the set screw and is fixedly (non-rotatably) connected to the set screw, i.e., does not rotate relative to the set screw. Axially, the cap is secured only by friction so that it can be easily removed by the user by a lever action and the rotational limitation of the set screw can thus be canceled easily.
When the set screw has been properly adjusted before mounting of the cap during servicing or before delivery, it must be ensured that the cap is pushed on in correct position so that the adjustment safeguard is effective. However, the cap—accidentally or wantonly—can be positioned incorrectly so that an effective limitation of the maximally supplied fuel quantity under full load is not ensured.